Plants having one or more enhanced yield-related traits and a method for making the same

A method for enhancing one or more yield-related traits in plants compared to control plants under conditions when nitrogen is not limiting, comprising the steps of introducing and expressing in a plant cell or plant a nucleic acid encoding a polypeptide, wherein said polypeptide

• (i) is a basic, small protein and
• (ii) has no detectable Interpro domain when analysed with the Interpro software, Release 42.0, 4 Apr. 2013, and
• (iii) has a molecular mass of equal to or less than 15000 Da, and
• (iv) comprises at least 15% by number of amino acids with a basic side chain, and
• (v) comprises no more than 30% by number of amino acids with a basic side chain, and
• (vi) has a content of sulphur containing amino acids of equal to or less than 5% by number, and
• (vii) contains equal to or less than 5% by number of aromatic amino acid residues and/or equal to or more than 16% by number of acidic amino acids, yet not more than 30% by number of acidic amino acids;
• hereinafter called SPY polypeptide
• and
• cultivating said plant cell or plant under conditions promoting plant growth and development, particularly of plants having one or more enhanced yield-related traits relative to control plants when nitrogen is not limiting.